Field of the Invention
The invention relates to an electronic-hydraulic transmission control module with an electronic control unit arranged on a hydraulic plate, and at least one sensor, in particular for a motor vehicle. The invention further pertains to a method for manufacturing such a transmission control module.
In prior art transmission control modules such as are used in automatic transmissions or in automated manual shift transmissions, sensors for measuring pressures in a hydraulic duct of a hydraulic plate normally have to be sealed twice in order to prevent hydraulic fluid from escaping. This pressure sensor is frequently integrated in a metallic base plate of the housing of an electronic control unit. This base plate is then mounted on a hydraulic plate, the pressure sensor projecting into a hydraulic duct of the hydraulic plate. A first O-ring is thus required between the pressure sensor and the opening in the base plate, and a second O ring is required between the base plate and the hydraulic plate.
Commonly assigned published patent application US 2001/011478 A1, and the corresponding German published patent application DE 198 34 212 A1, disclose a transmission control unit whose base plate has a hole wherein a pressure sensor is held in a pressure-tight and frictionally locking fashion. The base plate is in turn sealed with respect to a hydraulic unit using a seal. In order to achieve the pressure-tight attachment, the base plate must be made relatively thick at least in the region of the sensor.
German utility model DE 295 13 950 U1 relates to a transmission control unit which does not need a base plate. A circuit carrier that is fitted with the electronic control unit on its upper side and with a pressure sensor chip on its underside is arranged directly on a hydraulic unit. A duct in the hydraulic unit wherein hydraulic oil is located leads directly to the pressure sensor and is covered by it. Because the hydraulic oil is pressurized, forces are transmitted directly to the circuit carrier which is usually a ceramic substrate. In addition, it is difficult to seal off the duct from the surroundings.
It is accordingly an object of the invention to provide an electronic-hydraulic transmission control module and a manufacturing method for such a transmission control module, which overcome the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which permit simple and oil-tight integration of a sensor, which acquires states of the hydraulic fluid.
With the foregoing and other objects in view there is provided, in accordance with the invention, an electronic-hydraulic transmission control module, comprising:
a hydraulic plate formed with at least one duct for hydraulic fluid and with an opening having a wall;
an electronic control unit disposed on the hydraulic plate;
at least one solenoid valve connected to the electronic control unit for controlling the hydraulic fluid;
at least one sensor connected to the electronic control unit, the sensor being caulked in the wall of the opening, forming a plastic deformation.
Since the sensor is inserted directly into the hydraulic plate, it is possible to dispense with a seal between a base plate of an electronic module and the hydraulic plate. By caulking or pressing the sensor into the hydraulic plate it is also possible to dispense with a seal between the wall of the opening in the hydraulic plate and the sensor. There is therefore no need either for sealing elements or for parts for attaching the sensor.
In accordance with an added feature of the invention, the sensor has a body formed with at least one circumferential depression in which deformed material of the wall brings about frictional engagement (force lock) and a form lock (positive lock) with the body.
In accordance with an additional feature of the invention, the electronic control unit has a circuit carrier mounted directly on the hydraulic plate.
In accordance with another feature of the invention, a cover is sealed to the hydraulic plate and encloses the electronic control unit and the sensor.
In accordance with a further feature of the invention, at least one solenoid valve is attached to the hydraulic plate and disposed outside and spaced apart from the cover.
In accordance with again an added feature of the invention, the body of the sensor is composed of a steel alloy, and the hydraulic plate is composed of aluminum, polyamide, or polybutylene therephtalate. That is, if the material of the hydraulic plate is meant to deform during the caulking of the sensor, steel is particularly suitable as a material for the body or the housing of the sensor and aluminum, polyamide (PA66) or polybutylene therephtalate (PBT) is suitable as the material for the hydraulic plate. On the other hand, if the body of the sensor is meant to deform, its material must be more readily deformable than that of the hydraulic plate.
With the above and other objects in view there is also provided, in accordance with the invention, a method of manufacturing an electronic-hydraulic transmission control module. The method comprises the following steps:
providing an hydraulic plate formed with an opening having a given width and a sensor having a larger width (i.e., clearing dimension) than the given width (clearing dimension) of the opening;
caulking the sensor with the larger width in the opening;
mounting an electronic control unit on the hydraulic plate; and
producing an electrical connection between the sensor and the electronic control unit.
In accordance with a concomitant feature of the invention, the opening and the sensor are substantially round, and the width and the given width are diameters.
The sensor is preferably a pressure sensor, a rotational speed sensor or a temperature sensor which takes measurements within an automatic motor vehicle transmission or within an automated manual shift transmission.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in en electronic-hydraulic transmission control module and manufacturing method, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.